JP7130772B2 - Parking lock units and drives with such parking lock units - Google Patents

Description

The invention relates to a parking lock unit, in particular for a motor vehicle drive with an electric motor, and a drive with such a parking lock unit.

The drive can be provided with a parking lock unit, the main task of which is to ensure that the parked vehicle is stopped. Particularly with the use of electrically actuated parking brakes instead of mechanically actuated parking brakes, parking locks are increasingly becoming the primary safeguard against unintended movements of the vehicle. In this case, the locking action is usually achieved by a locking element that engages the parking lock gear in a form-locking manner. In this case, the parking lock unit is designed mechanically or electromechanically to eliminate unwanted locking conditions at vehicle speeds in excess of 5 km/h. The parking lock unit can thus be locked at less than 5 km/h. The resulting torque impulse loads the mechanical elements in the driveline between the parking lock and the tires on the one hand and the drive unit on the other hand, so that the dimensional design is required.

A parking lock unit for an electric drive is known from WO 2018/001476. The parking lock unit comprises a parking lock casing and a sleeve-like shaft rotatably supported in the parking lock casing and having a connection profile for a non-rotatable connection to the drive shaft of the electric drive. and a mounting portion. A lock gear is non-rotatably connected to the shaft mount and has a straight gear body. A locking element movably supported in the parking lock casing is moveable by a controllable actuator between a closed position for locking the locking gear and an open position for releasing the locking gear.

The problem underlying the present invention is to propose a parking lock unit for a drive whose construction reduces the stress on the mechanical elements of the drive when the parking lock is engaged. The object is also to provide a corresponding parking lock unit with such a parking lock unit that enables a reliable interruption of the drive train, is able to absorb the kinetic energy when the parking lock is engaged, and requires little installation space. is to propose a driving device for

To solve this problem, there is provided a parking lock unit, in particular for a drive with an electric motor, which drive is supported rotatably about a rotation axis by means of a parking lock housing and at least one bearing. a parking lock gear having a connecting section and a locking section connected to each other via a web section and supported in the parking lock casing; a locking element capable of locking and unlocking rotational movement of the parking lock gear about the longitudinal axis of the parking lock gear; a controllable lock actuator capable of reversibly transitioning to the proposed.

By locking the parking lock, the kinetic energy of the rotating part of the drive train between the parking lock gear and the tires on the one hand and the drive unit between the parking lock gear and the drive unit on the other hand is converted into impact energy. be done. Due to the collision, the parking lock gear is subjected to a radial force component and a tangential force component which further induces a torsional moment. Owing to the axial offset of the locking section with respect to the coupling section, the proposed parking lock unit is free from the power transmission path between the parking lock and the tire on the one hand and the parking lock and the drive unit on the other hand. Advantageously, the torsional length of the power transmission path between is increased and the torsional stiffness of the power transmission path is reduced. Furthermore, the locking section of the parking lock gear can be radially deformed, so that the deformation energy can be elastically stored in the parking lock gear. Due to the two effects mentioned above, when the parking lock is engaged, a greater proportion of the impact energy can be elastically converted into strain or deformation energy and the load on the mechanical elements of the drive is reduced. Thus, in one possible embodiment, the center plane of the locking section of the parking lock gear is a first distance from the center plane of the coupling section of the parking lock gear that is greater than the smallest axial thickness of the web section. may have

As a central plane of a component or a central plane of a section of a component, respectively, an extension of each component or section of a component extending perpendicular to the axis of rotation of the respective component and along its axis of rotation be understood to be a virtual plane positioned in the middle of the

The locking section of the parking lock gear is a radially outwardly disposed, generally ring-shaped portion that includes a plurality of locking recesses evenly distributed along its circumference. A locking element can be engaged with the locking recess to restrict the rotational freedom of the parking lock gear. Together with the locking element, the recess can be configured in such a way that, when a critical rotational speed is exceeded, the locking element is retracted and thus locking of the parking lock is mechanically prevented (ratcheting). The width B1 of the locking section is selected in such a way that the forces and pressures which occur when locking the parking lock can be reliably transmitted.

The coupling section of the parking lock gear is a substantially ring-shaped portion forming the radially inner portion of the parking lock gear. The cross-section of the semi-longitudinal section of the connecting section can be T-shaped. In this case, the coupling section has a substantially sleeve-shaped portion extending about the axis of rotation of the parking lock gear and a portion projecting radially outwardly from this portion. A sleeve-like portion of the coupling section serves to couple the parking lock gear to the rotatably supported portion of the drive. For this purpose, the region of the inner circumference can be cylindrically shaped for a press fit, or the connecting structure can have, for example, spline teeth. Various configurations are also conceivable as a shaft-hub connection that permits a non-rotatable connection. The width B3 of the sleeve-like portion is defined by the area capable of transmitting torque in contact with the rotatably supported element of the drive. In this case, the width B3 is selected in such a way that the resulting torque can be reliably transmitted by the shaft-hub connection. In one possible embodiment, the ratio of the parking lock gear width B1 at the outer diameter to the parking lock gear width B3 at the inner diameter is less than 1.0, in particular less than 0.85, in particular 0.8. and/or greater than 0.7, in particular greater than 0.75. The sleeve-shaped part may be axially adjoined by a positioning step which axially positions the parking lock gear with respect to the component to which the parking lock gear is fixedly connected. configured to be positioned and supported by the

The connecting section may include radially outwardly projecting portions from the web section that serve for the predetermined introduction of forces and torques into the sleeve-like portion of the connecting section. This radially outwardly projecting part can be arranged centrally with respect to the sleeve-like part, which ensures a uniform, in particular symmetrical, load distribution in the shaft-hub connection. The transition to the coupling section can be arranged at the point where the gear body transitions from straight to bent. It is also conceivable for the radially outwardly projecting part to be omitted and for the web section to be directly connected to the sleeve-shaped part of the connecting section.

The central plane of the locking section and the central plane of the coupling section are spaced apart along the longitudinal axis of the parking lock gear so that the parking lock gear has an offset shape. In one possible embodiment, the ratio of the first spacing A1 to the outer diameter Da of the parking lock gear is greater than 0.08, in particular greater than 0.10 and/or less than 0.5. , in particular less than 0.4. In another embodiment, the ratio of the first spacing A1 to the parking lock gear width B1 at the outer diameter is greater than 0.85, in particular greater than 0.9, in particular greater than 0.95, and / or may be less than 3, in particular less than 2.7.

A web section extends between the above-mentioned sections of the parking lock gear and the shape of the web section reduces the radial and torsional stiffness of the parking lock gear compared to a straight gear body. selected to be The web section can therefore also be referred to as the spring section. In one possible configuration, for this purpose the web section can have thinner walls than the locking section and the connecting section, at least in partial regions. In another embodiment for this, the width or thickness of the wall of the web section is, at least in a partial region, radially outwardly to radially inwardly such that the stress occurring in this partial region is at least approximately constant. May be increasing. This results in effective material deformation with low torsional or bending stiffness. An at least approximately constant stress is also understood to include a ±5% deviation from the constant design nominal stress.

In one possible embodiment, the parking lock gear can be arranged on a protruding free shaft end of the rotatably supported part of the drive. Due to the radial force component during locking of the parking lock, the free shaft end can bend like a bending beam in the direction of action of the force. As a result, additional deformation energy can be stored elastically at the free shaft end, thus reducing the load on peripherally located machine elements.

In another embodiment, the central plane of the locking section of the parking lock gear is arranged axially between the central plane of the coupling section of the parking lock gear and the central plane of the bearing adjacent to the parking lock gear. It can be. Adjacent bearings are understood to be in each case bearings which are arranged with the parking lock gear on the rotatably supported part of the drive and which have a minimum distance to the parking lock gear. sea bream. This makes it possible to achieve a compact axial constructional dimension of the parking lock unit. Furthermore, this causes the force application planes of the radial locking forces to be shifted in the direction of the respective adjacent bearings, thus reducing the resulting load on the bearings. In particular, this allows the locking section to be arranged above the adjacent bearing. For this purpose, in one embodiment, the ratio of the first spacing A1 to the second spacing A2 between the central plane of the coupling section of the parking lock gear and the central plane of the bearing adjacent to the parking lock gear. may be greater than 0.25, in particular greater than 0.35 and/or less than 1.

A parking lock casing houses a lock element and a lock actuator. Furthermore, the parking lock casing forms a space in which the parking lock gear can be accommodated.

A further configuration of the invention is a drive for an electric motor drive of a motor vehicle, comprising a parking lock unit as described above, a housing assembly and a motor shaft connected to the housing assembly and drivable in rotation. an electric motor, at least one transmission mechanism shaft, and an output branch unit, wherein the motor shaft, the at least one transmission mechanism shaft, and the output branch unit are each rotatably supported in the casing assembly; The rotatably supported parts, which are connected to one another via at least one gear stage for movement and torque transmission and to which the parking lock gear is connected in a non-rotatable manner, are the motor shaft, It relates to the drive, which is one of the parts of the transmission shaft and the output branch unit.

A drive with a parking lock unit according to the invention offers the same advantages as those described above in connection with the parking lock unit, which are omitted here.

A preferred embodiment will now be described with reference to the drawings.

1 is a longitudinal sectional view showing a parking lock unit according to the invention; FIG. Fig. 1b is a cross-sectional view of part of the parking lock unit of Fig. 1a; FIG. 2 is a perspective view showing a parking lock gear of the parking lock unit of FIG. 1; 2 shows a perspective view of an electric drive with a parking lock unit according to the invention from FIG. 1; FIG. FIG. 4 is a longitudinal sectional view showing the driving device of FIG. 3 along line IV-IV;

1 and 2, which are described together below, show a parking lock unit 2 according to the invention for the drive of a motor vehicle. Parking locks are commonly used to reversibly lock the driveline of the drive system to prevent unintentional starting or movement of the vehicle.

The parking lock unit 2 comprises a parking lock casing 3, a parking lock gear 5 which is non-rotatably connected to a rotatably supported portion 22 of the drive unit, and is movably supported within the parking lock casing 3. and a locking element 6. The locking element 6 can be reversibly transferred from a locked position to a released position by means of a controllable actuator 7 . The rotatably supported part 22 is in this case configured as a shaft, but is not limited to this.

The locking gear 5 has a radially outwardly positioned locking section 8 whose outermost circumferential surface along the outer diameter Da has a plurality of evenly distributed locking sections. A stop recess 13 is arranged in which a locking tooth 14 of the locking element 6 can engage in a form-locking manner. The locking element 6 is shown in the locking position in which it is positively connected with the locking gear 5, so that a rotational movement of the locking gear 5 about its own longitudinal axis is prevented. Starting from the lock position, the actuator 7 can reversibly shift the lock element 6 to the release position. At the release position, the lock element is positioned outside the action area of the lock gear 5, so that it cannot rotate relative to the lock gear 5. The coupled shaft 22 is freely rotatable. The locking section 8 has a width B1 which is dimensioned to ensure that the parking lock gear 5 can withstand the forces and pressures caused by locking the parking lock.

The locking section 8 is followed radially inwardly by a web section 9 , which in this embodiment is inclined at an installation angle α of approximately 45° with respect to the axis of rotation of the parking lock gear 5 . Thus, the central width or thickness B2 of web section 9 corresponds to approximately 25% of width B1 of locking section 8 . In this case, the width or thickness B2 of the web section 9, which varies from radially outward to radially inward, is chosen such that the stresses occurring therein are approximately constant. Based on the width or thickness B2 and the setting angle α, in addition, the twisting and bending properties of the web section 9 can be adjusted, so that these can be designed variably according to the application. Alternatively, it is also conceivable for the web section 9 to have a non-straight extension, in particular a meandering extension.

The parking lock gear 5 furthermore has a coupling section 10 on the radially inner side, which couples the parking lock gear 5 to the shaft 22 . In the illustrated embodiment the connection is formed as a splined shaft toothing with a nominal diameter Di. Alternatively, other shaft-hub connections are also conceivable, for example a press fit. The cross-section of the connecting section 10 in a semi-longitudinal section is T-shaped. The width B3 of the torque-bearing area of the cylindrical portion can be selected to ensure that the generated torque can be transmitted from the parking lock gear 5 to the shaft 22 . In the configuration shown, the width B1 of the locking section 8 corresponds to approximately 0.75 times the width B3 of the coupling section 10 . Axially following the cylindrical portion of the coupling section 10 a positioning step 11 extends, with which the parking lock gear 5 is axially positioned relative to the shaft 22 and supported. obtain. The radially outwardly projecting portion of the connecting section 10 essentially serves to connect the connecting section 10 to the web section 9 . Depending on the configuration of the web section 9, this part may therefore be omitted. The locking section 8 is axially offset with respect to the coupling section 10 . In this case, a spacing A1 is formed between an imaginary central plane E1 of the locking section 8 and an imaginary central plane E2 of the coupling section 10, which extends perpendicularly to the axis of rotation of the parking lock gear 5. FIG. The first spacing A1 in this embodiment approximately corresponds to the width B1 of the locking section or approximately 15% of the outer diameter Da of the parking lock gear 5, but is not limited thereto.

When the lock element 6 engages the parking lock gear 5, the kinetic energy of the rotating members of the power transmission path (drive train) to which the parking lock mechanism is connected is converted into impact energy. A collision causes a radial force component and a tangential force component, which additionally induces a torsional or braking moment, to act on the parking lock gear 5 . Due to the axial offset of the planes E1 and E2 and the arrangement of the web section 9 between them, the torsional length of the driveline is increased and the torsional stiffness of the driveline is reduced. . Furthermore, the locking section 8 of the parking lock gear 5 can be radially deformed. Due to the above-described two actions, a large proportion of the impact energy when the lock element 6 engages the parking lock gear 5 is converted into strain energy or (elastic) deformation energy, so the load on the surrounding mechanical elements is reduced. reduced.

The parking lock casing 3 comprises, in the illustrated embodiment, a first casing section 4 forming a ring chamber and a second casing section 4' in the form of a casing cover which is screwed to the first casing section 4. including. The first housing section 4 is formed in one piece with the transmission housing 32 of the drive. Alternatively, it is also conceivable that the parking lock unit 2 can be constructed modularly and that the parking lock housing 3 is constructed in such a way that the housing section 4 can be connected to the housing of the drive.

FIGS. 3 and 4, which are described together below, show an electric drive 17 with the parking lock unit 2 according to the invention from FIGS.

The electric drive 17 comprises an electric machine 18, a reduction transmission 19 drivingly connected to the electric machine 18 for transmitting torque, a parking lock unit 2 as described above, and a reduction transmission for transmitting torque. and a differential gear 20 drivingly connected to 19 . The electric drive 17 also has a housing assembly 15 in which an electric machine 18, a reduction transmission 19, a parking lock unit 2 according to the invention and a differential gear 20 are arranged. .

The reduction transmission mechanism 19 includes a transmission mechanism shaft 22, the longitudinal axis of which is arranged parallel to the longitudinal axis of the motor shaft 16, and the transmission mechanism shaft 22 is divided into two It is rotatably supported via bearings 24 and 25 . The transmission mechanism shaft 22 may be called an intermediate shaft. A switchable drive gear 27 is carried on the transmission shaft 22 and meshes with the drive pinion 21 of the motor shaft 16 . A driven pinion 28 is non-rotatably coupled to the transmission shaft 22 and meshes with a ring gear 29 to drive the differential gear 20 . The ring gear 29 is rigidly connected to the differential cage 30 of the differential gear 20 and may be constructed integrally with the differential cage, for example.

The parking lock gear 5 of the parking lock unit 2 is connected to the free shaft end 23 of the transmission shaft 22 in a rotationally fixed manner via a shaft-hub connection and is axially fixed by means of a snap ring 26 . ing. The parking lock gear 5 has a locking section 8 , a web section 9 and a coupling section 10 . The central plane E1 of the locking section 8 has a smaller distance to the central plane E3 of the bearing 24 than to the central plane E2 of the connecting section 10 . The locking section 8 is arranged axially partially overlapping the casing section which rotatably supports the bearing 24 . As a result, the axial installation space of the electric drive 17 can be reduced. Furthermore, the force acting surface of the radial force component of the impact when locking element 6 engages parking lock gear 5 moves toward bearing 24 . This reduces the load acting on the bearing 24 .

The web section 9 allows the power transmission path between the parking lock gear 5 and the driven shaft (not shown) of the differential 20 on the one hand and the power transmission path between the parking lock gear 5 and the drive unit on the other hand to The combined torsional length is increased and the torsional stiffness of the driveline is reduced. Furthermore, the locking section 8 can be displaced radially when the parking lock is locked. Both of these actions make it possible to convert more of the energy of the impact when the locking element 6 engages the parking lock gear 5 into strain or (elastic) deformation energy, and to the mechanical elements of the electric drive 17 . load is reduced.

When the parking lock gear 5 is radially loaded, the free shaft end 23 can likewise be displaced radially in the force introduction direction, like a bending beam, so that the free shaft end By arranging the parking lock gear 5 at 23, the deformation energy can additionally be absorbed.

The casing assembly 15 is assembled from a plurality of individual casing parts. In particular, the casing assembly 15 comprises a first casing section 31 in which the electric machine 18 and the bearings 25 of the transmission shaft 22 are housed, and a second and intermediate casing section 32 in which the differential gear 20 and the bearings 24 are housed. Includes plate 33 . The intermediate plate 33 is arranged between the first casing sections 31,32 and is rigidly connected to them. The parking lock housing 3 is partially integrated into the housing section 32 in this embodiment. However, it is also conceivable for the parking lock housing 3 to be formed separately and to be detachably connectable to the housing section 32 .

2 parking lock device 3 parking lock casing 4, 4' casing section 5 locking gear 6 locking element 7 actuator 8 locking section 9 web section 10 coupling section 11 positioning step 12
13 locking recess 14 locking toothing 15 casing assembly 16 motor shaft 17 electric drive 18 electric machine 19 reduction transmission 20 differential gear 21 drive gear 22 transmission shaft 23 free shaft ends 24, 24', 24'' bearings 25, 25', 25'' Bearing 26 Snap ring 27 Drive gear 28 Driven gear 29 Ring gear 30 Differential cage 31 Casing section 32 Casing section 33 Intermediate plate A Spacing B Width E Central plane α Installation angle

Claims (8)

A parking lock unit (2), in particular for a drive (17) with an electric motor (18),
a parking lock casing (3);
A portion (22) of said drive (17) supported rotatably about an axis of rotation (X1) by at least one bearing (24, 24', 24'', 25, 25', 25'') ) and having a connecting section (10) and a locking section (8) connected to each other via a web section (9);
a locking element supported in said parking lock casing (3) and capable of locking and releasing rotational movement of said parking lock gear (5) about its longitudinal axis; 6) and
A controllable lock actuator (7) capable of reversibly moving said locking element (6) between a position locking said parking lock gear (5) and a position releasing said parking lock gear (5). When,
in a parking lock unit (2) comprising
The parking lock gear (5) is formed such that the locking section (8) is axially displaced with respect to the coupling section (10) ,
The wall thickness (B2) of said web section (9) increases, at least in partial areas, from radially outward to radially inward such that the stresses occurring in said partial areas are at least approximately constant . A parking lock unit (2), characterized in that: A parking lock unit (2), in particular for a drive (17) with an electric motor (18),
a parking lock casing (3);
A portion (22) of said drive (17) supported rotatably about an axis of rotation (X1) by at least one bearing (24, 24', 24'', 25, 25', 25'') ) and having a connecting section (10) and a locking section (8) connected to each other via a web section (9);
a locking element supported in said parking lock casing (3) and capable of locking and releasing rotational movement of said parking lock gear (5) about its longitudinal axis; 6) and
A controllable lock actuator (7) capable of reversibly moving said locking element (6) between a position locking said parking lock gear (5) and a position releasing said parking lock gear (5). When,
in a parking lock unit (2) comprising
The parking lock gear (5) is formed such that the locking section (8) is axially displaced with respect to the coupling section (10),
characterized in that the parking lock gear (5) is arranged on a protruding free shaft end (23) of the rotatably supported part (22) of the drive (17), Parking lock unit (2). The center plane (E1) of the locking section (8) of the parking lock gear (5) is located relative to the center plane (E2) of the coupling section (10) of the parking lock gear (5) to the web section 3. Parking lock unit (2) according to claim 1 or 2 , having a first spacing (A1) greater than the smallest axial thickness (B2) of the parking lock unit (2) . The central plane (E1) of the locking section (8) of the parking lock gear (5) is axially aligned with the central plane (E2) of the coupling section (10) of the parking lock gear (5). , the center plane (E3) of the bearings (24, 24', 24'', 25, 25', 25'') adjacent to the parking lock gear ,
the central plane (E2) of the coupling section (10) of the parking lock gear (5) and the bearings (24, 24', 24'', 25, 25', 25) adjacent to the parking lock gear; '') with the median plane (E3) the ratio of said first spacing (A1) to the second spacing (A2) is greater than 0.25 and less than 1. 4. Parking lock unit (2) according to 3 . the ratio of the first spacing (A1) to the outer diameter (Da) of the parking lock gear (5) is greater than 0.08 and less than 0.5;
Claim 3, wherein the ratio of said first spacing (A1) to the width (B1) of said parking lock gear (5) at said outer diameter (Da) is greater than 0.85 and less than 3 . Or the parking lock unit (2) according to 4. The ratio of the width (B1) of the parking lock gear (5) at the outer diameter (Da) to the width (B3) of the parking lock gear (5) at the inner diameter (Di) is less than 1.0 , and parking lock unit (2) according to claim 5 , which is greater than 0.7. 7. Claims 1 to 6 , characterized in that the web section (9) has, at least in partial areas, a smaller wall thickness than the locking section (8) and the connecting section (10). parking lock unit (2). A drive device for driving an electric motor of a motor vehicle, comprising:
a parking lock unit (2) according to any one of claims 1 to 7 ;
a casing assembly (15);
an electric motor (18) having a rotatably driven motor shaft (16) connected to the casing assembly (15);
at least one transmission shaft (22);
an output branching unit (20);
including
The motor shaft (16), the at least one transmission mechanism shaft (22) and the output branch unit (20) are each rotatably supported in the casing assembly (15) for motion and torque transmission. are connected to each other via at least one transmission stage for
The rotatably supported portion (22), to which the parking lock gear (5) is non-rotatably connected, comprises the motor shaft (16), the transmission mechanism shaft (22) and the output branch unit (20). ), one of the parts of the drive.

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